Efficient Proton Conduction through [N···X···N]<sup>+</sup> Halogen Bond Coordination in Halogen‐Bonded Organic Frameworks
Qi Zhao, Siyi Lin, Penghao Sun, Ya Lu, Qian Li, Zhen‐Nan Tian, Xuguan Bai, Jike Wang, Lu Wang, Shigui Chen
Abstract
Abstract Advancing anhydrous proton‐conducting materials is essential for the fabrication of high‐temperature (>373 K) polymer electrolyte membrane fuel cells (HT‐PEMFCs) and remains a significant challenge. Herein, halogen‐bonded organic frameworks linked by [N···I··N] + interactions are reported as outstanding high‐temperature conductive materials. By incorporating carbazole groups into the monomers, two highly crystalline halogen‐bonded organic frameworks ( XOF‐CSP/CTP ) are constructed. These XOFs exhibit a high intrinsic conductivity (σ = 1.22 × 10 −3 S cm −1 ) under high‐temperature anhydrous conditions. Doping the XOFs with H 3 PO 4 allows the nitrogen sites and I + sites on the pore walls to stabilize and tightly confine the H 3 PO 4 network within the porous framework through hydrogen bonding, thereby enhancing proton conductivity under anhydrous conditions (σ = 1.02 × 10 −2 S cm −1 ). Temperature‐dependent curves and theoretical calculations indicate that proton transport is governed by a low‐energy barrier hopping mechanism. These materials exhibit excellent stability and maintain high proton conductivity across a broad temperature range. This work provides a new platform for designing anhydrous proton‐conducting materials with significant potential as high‐temperature proton exchange membranes.